With nearly all votes counted, 65% supported the new tax, while 35% opposed it. The measure would impose a special 15% excise tax on marijuana to help fund school construction, along with a 10% sales tax to bolster marijuana-related law enforcement efforts.

The passage was widely expected, despite opponents arguing it's unfair to single out marijuana for higher taxation than products such as beer.

Strong support for the measure is pegged largely to the money it is expected to bring in. The nonpartisan Colorado Legislative Council projects that the measure will generate nearly $70 million in additional state tax revenue next year.

There were 30 other measures on the ballot in six states Tuesday, all of which were too early to call for CNN. Here are highlights from a few:

Colorado: secession

Voters in 11 counties in northern Colorado are being asked if they want to secede from the state. Ten counties in conservative, rural northeastern Colorado would theoretically form a 51st state known as North Colorado. Moffat County, located in the northwest corner of the state, would become a panhandle for neighboring Wyoming.

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Colorado conservatives want to secede

The plan has no chance of becoming reality. Among other things, it would also require statewide and congressional approval. But approval or even a close vote at the county level would send a loud message of growing grassroots conservative anger toward a more liberal Denver-based Democratic establishment that has taken up controversial measures related to gun control, gay rights and green energy.

With more than 50,000 votes counted in Weld County, the most populated county of those trying to secede, 58% of votes were against secession and 42% were in favor of it. CNN, however, does not yet have a projection on this measure.

Similar secession measures have been floated in a number of other states in recent years in a reflection of the country's growing ideological and partisan divide.

Washington: Labeling genetically modified food

Voters in Washington state are considering a hotly contested initiative that would require labeling all foods containing genetically modified ingredients. The measure pits local consumer advocates, who argue that the measure is needed for consumers to make better informed choices, against large agribusinesses such as Monsanto, which argue that such a law would spook potential customers and unfairly imply that such products are unsafe.

Washington is the second state to consider such a ballot measure. A similar proposal was narrowly rejected by California voters last year.

With more than 800,000 votes counted, 53% of Washington State voters opposed the labeling, while 47% supported it. It is still, however, too early for CNN to call this race.

According to the nonpartisan National Conference of State Legislatures, 95 bills relating to the issue have been introduced in various legislatures so far this year -- a reflection of growing public interest in the controversy surrounding genetically modified foods.

Other noteworthy measures

Voters in New Jersey are considering whether to amend their constitution to raise the state minimum wage from the federal level of $7.25 to $8.25 per hour. Future annual increases would be tied to changes in the cost of living. Eighteen states have a minimum wage that exceeds the federal requirement, according to the NCSL.

New York voters are being asked to revise their constitution to allow the legislature in Albany to authorize seven casinos, with the goal of generating new revenue for public schools and potentially cutting property taxes.